Steam-air-thermal power plant



May 31, 1949 w, KARRER 2,471,755

STEAM-AIR-THERMAL POWER PLANT Filed March 1, 1945 feed line "2.

Patented May 31, 1949 OFFICE STEAM-AIR-THERMAL rowan PLANT Werner Karrer, Zurich, Switzerland, assignor to Maschinenfabrik. Oerlikon, Zurich-Oerlikon,

Switzerland Application March 1, 1945, Serial No. 580,438

In Switzerland January 5,1944

Section 1, Public Law 690, August 8, 1946 Patent expires January 5, 1964' Claims. 1

In steam-gas-thermalpower plants any increase of the efficiency by an intermediate heating of the air working in the turbine and by increasing the amount of air over that necessary for the combustion is very limited. To increase the efficiency ofa turbine plant it would seem feasible to introduce more fuel to heat a larger amount of lair.v .By calculation it has been found that'by doing so the temperatureof the gases of combustion after leaving the steam boiler would be dangerously highand might injure the material of the steamtsu-perheater or air heater. If the temperature remains within the allowable limits the heat after leaving the steam boiler would not suiiice to heatta larger amount of air.

The object of the present invention is to provide means to increase the efficiency of power plants of the character described by mixing hot gases with the gases of combustion after the same have left the steam boiler. The hot gases may be taken from the combustion chamber in advance of the steam boiler or the said hot gases may be produced in a separate chamberof combustion.

In the accompanying drawing two embodiments of my invention are shownby way of examples each .in sectional elevation in a diagram- .matical manner.

In Fig. l of the drawings I denotes a tubular steam boiler to which fresh water is fed by a The boiler I is arranged .above a grate The steam leaving the boiler 'I passes through a superheater 4 arranged in the :path of the combustion gases. The steam superheatedin the superheater '4 passes through a pipe 5 to a steam turbine= 6 and from there to a condenser E. The steam turbine 6 is aprime mover destined to drive anymachine 9 doing-mechanicaiwork. The feed water is fed to the boiler I by any suitable pump 8. The coil I2 denotes a device to heat air and the heated air drives a turbine I3 by which a compressor I4 and a machine I5 for performing useful work is driven.

The amount of air introduced into the air turbine plant is larger than the amount of air which is necessary to keep up the combustion of the fuel to produce steam in the boiler I. A portion of the exhaust air from the turbine I3 passes by pipe it under the grate 3. Through a pipe I! the remaining air is led to a feed water heater Iill. If not all the heat of the remaining air is used to pre-heat the feed water the surplus air may be conducted by a pipe I8 to any place to utilize the heat for instance to warm rooms or goods.

The superheater I'2 for the air is arranged in advance of the superheater Afor the steam. The heating of the surplus ofsair necessary to increase the efiiciency takesup much-heat from the gases of combustion and the latter arrive at the steam superheater 4 at a comparatively low temperature.

To transfer the heat necessary for the superheater 4, hot gases lof c'ombu'st-ion are drawn from the combustion chamberabove the: grate 3 and are led by pipe I19 into the'sspaoe between the air heating device |21and the steam superheater 4 and are mixed with the gases of combustion which have already given off part of their heat to the steam boiler I and the air heater I2. In the pipe 1 9 a controlling valve 2'0 is arranged. The influx of the hot gases bypipeii Qfis arranged in such a manner that an intimate mixture of the ases of combustion :aiter the-air'heater I2 isattained.

In Fig. 2 a plant is shown in which hot gases are added to 'the-gases'=-of. combustion of the steam boiler in advance of the airhea'ter, and in which the hot gases are produced in a separate combustion chamber; The plant comprises two combustion chambers 29 and ttll, one for the steam -boiler A and one tor theairheater. The air for the combustion iswfed by the pipes 'ItI and I62 to the grates 34, .32. The steam turbine t is a back pressure turbine. "The feed water is delivered by pump '8 to :the preheating devices IDTI, H12, H33 and from. the latter into the boiler I. The "exhaust :gases from the steam :boiler A and from the air heater B tran'sfer part-of the residual heat to the feed water. Invtheair turbine an intermediate reheating is made use or; the said air turbine comprises two separate turbines I3 I, I32 which drive ancompressor' Wand any work producing machine I5. On the grate 32 sufiicient fuel may be burnt to supply the necessary heat for the air heaters I 2|, I22. Through a pipe I'9I a part of the gases of combustion of the steam boiler I is led to the air heater I2I and is mixed with the hot gases in advance thereof to prevent the rising of the temperature in advance of the air heater IZI to a too high degree. Through another pipe I92 gases of combustion of the steam boiler plant are led into the space between the two air heaters I2I, I22. The necessary pressure drop may be produced by a fan in the conduit IBI or by a valve in the conduit I62. In the pipes H, I92 dampers 21H, 202 are arranged to coin trol the temperature in advance of the heaters I2I, I22 and keep the temperature at a predetermined height. The air discharged from the air turbine I32 is led partly to the grates 3|, 32

and. partly to the feed water heater H11 and from there to any other place for heating purposes.

The mounting of the steam and air heaters and the means to feed and to mix the hot gases with the gas of combustion of the steam boiler may be made in any suitable manner.

In both of the examples of the plant described more heat is fed to the air turbine plant by mix in with hot gases. The output of the air turbine might be increased still more. The efficiency of the entire plant is materially increased in comparison with a plant without the admixture of hot gases to the gases of combustion of the steam boiler.

What I wish to secure by United States Letters Patent is:

1. In a steam-air power plant, the combination with a steam generator comprising a steam boiler, a combustion chamber and steam superheater, of an air heater arranged between said steam boiler and said steam super-heater, and means for conducting a portion of the hot gases from said combustion chamber into the combustion gases where the latter enter the zone in which said steam super-heater is arranged while the remaining hot gases heat the boiler and the air heater.

2. In a steam-air power plant, the combination with a steam generator comprising a steam boiler, a combustion chamber and a steam superheater, of an air heater arranged between said steam boiler and said steam super-heater, a duct for conducting a portion of the hot gases from said combustion chamber into the combustion gases where the latter enter the zone in which said steam super-heater is arranged while the remaining combustion gases heat the boiler and the air heater, and means for controlling the amount of hot gases passing through said duct.

3. In a steam-air power plant, the combination, a steam generator comprising a steam boiler, a combustion chamber and a steam super-heater, an air heater arranged between said steam boiler and said steam super-heater, controllable means for conducting hot gases from said combustion chamber into the combustion gases where the latter enter the zone in which said steam superheater is arranged, a prime mover operated by the steam produced by said steam generator, a prime mover operated by the air heated by said air heater, means for conducting a portion of the air exhausted by said last mentioned prime mover into the combustion chamber of said steam generator, a feed water preheater, means for condensing the steam exhausted by said steam operated prime mover, means including a pump for conducting the condensed water through said preheater and into said steam boiler, and means for conducting the remaining portion of the air exhausted by said hot air operated prime mover through said preheater for heating the feed water passing therethrough.

4. In a steam-air power plant, the combination, a steam generator comprising a steam boiler, a combustion chamber and a steam super-heater.

an air heater arranged between said steam boiler and said steam super-heater, duct means including .a valve for conducting hot gases from said combustion chamber into the combustion gases where the latter, after having given off a part of their heat to said steam boiler, enter the zone in which said steam super-heater is arranged, a prime mover operated by the steam produced by said steam generator, a prime mover operated by the air heated by said air heater, means for conducting a portion of the air exhausted by said last mentioned prime mover into the combustion chamber of said steam generator, a feed water pump, a preheater for feed water, means for connecting the latter with said pump and with said boiler, and means for conducting the remaining portion of the air exhausted by said hot air operated prime mover through said preheater for heating the feed water passing therethrough.

5. In a steam-air power plant, the combination with a steam generator Comprising a steam boiler, a combustion chamber below said steam boiler and a steam super-heater in a zone above said steam boiler, of an air heater arranged in another zone above said steam boiler, and means for conducting a portion of the hot gases from said combustion chamber into the combustion gases where the latter enter the zone in which said steam super-heater is arranged.

WERNER KARRER.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 64,540 Kafer May 7, 1867 709,655 Webster Sept. 23, 1902 1,184,977 Meier May 30, 1916 1,554,154 Yarrow Sept. 15, 1925 1,588,568 Bennis June 15, 1926 1,702,264 Lorenzen Feb. 19, 1929 2,114,257 Thomas Apr. 12, 1938 2,404,938 Armacost July 30, 1946 2,410,457 Nettel Nov. 5, 1946 FOREIGN PATENTS Number Country Date 627,514 Germany Mar. 17, 1936 

